package com.aq.appserver.common.util;

import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;
import java.io.File;

import javax.imageio.ImageIO;

public class ImageUtil {
	
	  // 生成缩略图
    public static File saveImageAsJpg(String fromFileStr, String saveToFileStr, int width) throws Exception {
        BufferedImage srcImage;
        String imgType = "JPEG";
        if (fromFileStr.toLowerCase().endsWith(".png")) {
            imgType = "PNG";
        }
        // System.out.println(ex);
        File saveFile = new File(saveToFileStr);
        File fromFile = new File(fromFileStr);
        srcImage = ImageIO.read(fromFile);
        int originalImageWidth = srcImage.getWidth(null);  
        int originalImageHeight = srcImage.getHeight(null);  
        if (width > 0) {
            srcImage = resize(srcImage, width, (width*originalImageHeight)/originalImageWidth);
        }
        ImageIO.write(srcImage, imgType, saveFile);
        return saveFile;
    }

    public static BufferedImage resize(BufferedImage source, int targetW, int targetH) {
        // targetW，targetH分别表示目标长和宽
        int type = source.getType();
        BufferedImage target = null;
        double sx = (double) targetW / source.getWidth();
        double sy = (double) targetH / source.getHeight();
        // 这里想实现在targetW，targetH范围内实现等比缩放。如果不需要等比缩放
        // 则将下面的if else语句注释即可
        if (sx > sy) {
            sx = sy;
            targetW = (int) (sx * source.getWidth());
        } else {
            sy = sx;
            targetH = (int) (sy * source.getHeight());
        }
        if (type == BufferedImage.TYPE_CUSTOM) { // handmade
            ColorModel cm = source.getColorModel();
            WritableRaster raster = cm.createCompatibleWritableRaster(targetW, targetH);
            boolean alphaPremultiplied = cm.isAlphaPremultiplied();
            target = new BufferedImage(cm, raster, alphaPremultiplied, null);
        } else
            target = new BufferedImage(targetW, targetH, type);
        Graphics2D g = target.createGraphics();
        // smoother than exlax:
        g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
        g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));
        g.dispose();
        return target;
    }
}
